A typical philosophical example of a false statement used in many books is “She is a witch.” That’s because of the suppressed assumption that there are no witches.
But the assumption is false: there are numerous women today who call themselves “witches.”
Now it may be that the philosopher would object that these people are deluded about their own magical powers. Magic does not work. Or they are running a scam.
Or it may be that he thinks that even if there are witches, they are harmless and ought not to be hunted. I would dispute both of these propositions.